WASHINGTON, Dec. 21, 2011 /PRNewswire-USNewswire/ -- Illegal immigration was the fastest growing federal arrest offense between 2005 and 2009, increasing an average rate of 23 percent each year, the Bureau of Justice Statistics (BJS) announced today. In 2009, 84,749 suspects were arrested and booked for immigration offenses, up from 38,041 in 2005.

A federal arrest is a formal charge of violating federal law. Persons who were apprehended, detained, released or deported without a formal arrest charge were not included in the number of federal suspects arrested and processed.

During 2009, a record 183,986 suspects were arrested for federal offenses, up from 140,200 in 2005 and nearly double the 83,324 suspects arrested in 1995. Illegal immigration (46 percent) was the most common offense at arrest in 2009, followed by drug (17 percent) and supervision (13 percent) violations.

More than half (56 percent) of all federal arrests occurred in the five federal judicial districts along the U.S.-Mexico border: Southern California, Arizona, New Mexico and Western and Southern Texas. The federal caseload handled in these five districts in 2009 comprised more than a third of all federal defendants prosecuted (35 percent), convicted (35 percent) and sentenced to prison (37 percent).

Most federal defendants (77 percent) in cases terminated in 2009 had been detained prior to case disposition. Defendants were most likely to be detained when charged with immigration (95 percent), violent crime (87 percent), weapons (82 percent), and drug (81 percent) offenses. About 88 percent of defendants charged in the five judicial districts along the U.S.-Mexico border were detained in 2009.

Of the 193,234 matters concluded by U.S. attorneys in 2009, two out of three involved immigration (46 percent) or drug (20 percent) offenses. Immigration matters concluded increased an annual average of 31 percent since 2005, while drug matters declined an annual average of 1.4 percent.

About 48 percent of suspects in matters concluded were prosecuted by U.S. attorneys in 2009, compared to 60 percent of suspects in 2005. One reason for the decrease in prosecution by U.S. attorneys is the growth in immigration matters disposed by U.S. magistrates. About 67 percent of immigration offenders were disposed by U.S. magistrates in 2009, up from 46 percent in 2005.

Of the 95,000 federal cases concluded in 2009, 40 percent were represented by a public defender (up from 22 percent in 1995), 36 percent by a panel-appointed attorney (up from 32 percent in 1995) and 21 percent by a private attorney (down from 37 percent in 1995). Among cases terminated with a public defender in 2009, nearly 49 percent involved immigration offenses.

About 95,900 federal defendants were adjudicated in 2009, and most were convicted following a guilty plea (88 percent) or a bench or jury trial (3 percent). The median time from case filing to disposition was 6.5 months in 2009.

More than three-quarters (78 percent) of convicted defendants were sentenced to prison in 2009. The average prison term imposed on federal offenders in 2009 was 57 months, down from 61 months in 2005. Prison sentences in 2009 were an average of 82 months for drug offenses, compared to 113 months for violent offenses and 87 months for weapons offenses.

At year-end 2009, 393,810 persons were under some form of federal supervision. Of these, 62 percent were in secure confinement and 38 percent were in the community. Of offenders under active federal post-conviction supervision in the community, the majority of offenders (98,465) were on supervised release, compared to probation (22,748) and parole (2,158).

The number of federal prisoners age 55 and older nearly doubled, from 8,221 in 2000 to 15,323 in 2009. The median age of prisoners increased from age 35 in 2000 to age 37 in 2009. Most federal prisoners in 2009 were male (93 percent), black non-Hispanic (37 percent), and U.S. citizens (74 percent).

The reports, Federal Justice Statistics, 2009 (NCJ 234184) and Federal Justice Statistics, 2009 - Statistical Tables (NCJ 233464), were written by BJS statistician Mark Motivans. The reports, related documents and additional information about the Bureau of Justice Statistics' statistical publications and programs can be found on the BJS website at http://www.bjs.gov/.

The Office of Justice Programs (OJP), headed by Assistant Attorney General Laurie O. Robinson, provides federal leadership in developing the nation's capacity to prevent and control crime, administer justice, and assist victims. OJP has six components: the Bureau of Justice Assistance; the Bureau of Justice Statistics; the National Institute of Justice; the Office of Juvenile Justice and Delinquency Prevention; the Office for Victims of Crime; and the Office of Sex Offender Sentencing, Monitoring, Apprehending, Registering, and Tracking. More information about OJP can be found at http://www.ojp.gov.